J . Org. Chem., Vol. 44, RTo. 14, 1979 2533
P,P-Divinyl-P-phenethyl Tosylate ether and then the ethereal solution was poured onto a column of silica gel (50 times the amount of starting amine oxide). The ethereal solution of the product was then poured onto the column. Elution with diethyl ether (2 bed volumes) was followed by rotary evaporation of the solvent to give the carboxylic acid. The results are summarized in Table VI. Registry No. 1 (R = Ph), 19069-56-8;1 (R = p-CH,Ph), 70415-62-2; 1 (R = p-CHSOPh), 62557-46-4; 1 (R = p-(CHJ&Ph), 14377-42-5; 1 (R = i>-NO,Ph),30727-41-4;1 (R = (CHZ),,CH,), 70415-63-3; 2 (R = Ph), 70415-64-4;2 (R = p-CH,Ph), 70415-65-5; 2 (R = P-CHSOPh), 70415-66-6; 2 (R = P-NOZPh), 70415-67-7; 2 (R = p-(CH3)3CPh), 70415-68-8; 2 (R = (CH2)14CH3),70415-69-9; 3 (R = Ph), 66310-15-4; 3 (R = p-CHSPh), 70415-’70-2;3 (R = P-NOZPh),70415-71-3;3 (R = p-CH,OPh), 70415-?2-4;3 (R = p-(CH,)&Ph), 70415-73-5;3 (R =
(CHZ),,CHJ, 70415-74-6;4 (R = Ph), 50908-25-3;4 (R = P-CHSPh), 70415-75-7; 4 (R = p-NOzPh), 50908-24-2; 4 (R = p-CHaOPh), 70415-76-8;4 (R = p-(CH,),CPh), 70415-77-9;4 (R = (CH2)14CH3), 70415-78-0;6 (R = P-NOZPh),831-69-6;6 (R = Ph), 769-78-8; 6 (R = p-CHSPh), 2653-44-3; 6 (R = p-CHZOPh), 13351-86-5; 6 (R = p-(CHJ,CPh), 15484-80-7;7 (R = (CHZ)IdCH3),70415-79-1;7 (R = P-NOZPh), 70415-80-4; 7 (R = Ph), 70415-81-5;7 (R = p-CHSPh), 70415-82-6;7 (R = p-CHSOPh), 70415-83-7;7 (R = p-(CHS)&Ph), 70415-84-8; 2-pyridylcarbinol, 586-98-1; benzoyl chloride, 98-88-4; benzoic acid, 65-85-0; p-tert-butylbenzoic acid, 98-73-7;p-methylbenzoic acid, 99-94-5;p-methoxybenzoicacid, 100-09-4;p-nitrobenzoic acid, 62-23-7;palmitic acid, 57-10-3;2-(Npiperidyl)ethanol, 3040-44-6; p-methylbenzoyl chloride, 874-60-2; p-methoxybenzoyl chloride, 100-07-2; p-tert-butylbenzoyl chloride, 1710-98-1; p-nitrobenzoyl chloride, 122-04-3;palmitoyl chloride, 112-67-4.
Synthesis and Solvolysis of @,@-Divinyl-@-phenethyl Tosylate1s2 J a m e s W. Wilt* and Rein Niinemae3 Department of Chemistry, Loyola University of Chicago, Chicago, Illinois 60626 Received January 3, 1979
To seek aryl migration coupled with electrocyclic ring closure during solvolysis, we prepared and solvolyzed the title tosylate in aqueous dioxane and in acetic acid. The products were completely rearranged, both by vinyl (major) and phenyl (minor) migration. No cyclization via the sought electrocyclic closure was detected. The rate of acetolysis of the title tosylate was comparable to that of neophyl tosylate, indicating a balance of the opposing factors of inductive retardation and anchimeric acceleration centered in the vinyl groups.
In principle, the known process of aryl migration coupled with electrocyclic ring: opening’ found in eq 1 should have a converse process, viz., that of aryl migration coupled with electrocyclic ring closure as in eq 2. The two processes
+-
.
I
Scheme I PhCH,CN
(1)Electrocyclic Effects in Solvolysis. 2. Part 1: J. W. Wilt, T. P. Malloy, P. K. Mmkerjee, and D. R. Sullivan,J. Org. Chem., 39,1327 (1974). (2) Taken in part from the dissertation of R.N., Loyola University of Chicago, 1977. (3) University Fellow, 1975-1976. (4) The disrotatory cyclopropyl cation opening has many examples and is discussed in a number of texts: e.g. T. H. Lowry and K. S. Richardson, “Mechanism and Theory in Organic Chemistry”,Harper and Row, New York, N.Y., 1976, pp 647-50. The conrotatory pentadienyl cation closure is less referenced. A few recent studies are Y. Gaoni, Tetrahedron Lett., 371 (1977), N. W. K. Chiu and T. S. Sorensen, Can. J . Chem., 51, 2776 11973),and C. W. Shoppee and B. J. A. Cmke, J. Chem. Soc., Perkin Trans. 1, 1026 (1973).
0022-3263/79/1944-2533$01.00/0
-+
9
PhCM,G (1)
1
M CH,CH,OCH=CH,
2 3
CH,CH,OH CH,CH,OTs
4
CH=CH,
5
CH=CH,
6
CH=CH,
7
CH=CH,
8
CH=CH,
9
CH=CH,
2
+
8
7
9+--8-7+6-5-4
\‘
can be viewed, as t h e aryl group migrates, in terms of a disrotatory cyclopropyl cation ring opening (eq 1) and a c o n r o t a t o r y p e n t a d i e n y l cation ring closure (eq 2)reactions with considerable literature p r e ~ e d e n t . As ~ an initial investigation of this latter possibility, the synthesis and solvolytic rearrangement of 0,P-divinyl-P-phenethyl tosylate (9) has been studied. Although the desired result of eq 2 was not observed, certain synthetic and solvolytic items of interest were obtained, as well as a hindsight
1
6
2
3
5
3 14
conditions (yield, % ) CN 1. ClCH,CH, OCH=CH,, NaH, Me,SO (80) CN 2 . dilute HC1 ( 7 5 ) CN 3. TsC1, pyridine (72) CN a. KO-t-Bu. Me,SO ( 8 5 ) CONH-t-BU 5 . t-BuOH, HOAC, H,SO, (40) CONH, 6. BF, ,Et,O; c1, c=CCl, (9 1) COOH 7. i-AmONO, HCl(87) CH,OH 8. LiAlH, , Et,O (60) CH,OTs 9.‘TsCl, pyridine (70) G
rationalization for the absence of the closure process.
Results and Discussion After a number of unsuccessful attempts with other reagents, dialkylation of phenylacetonitrile was accomplished, using vinyl 0-chloroethyl ether. The bis vinyl ether 1 so obtained was then eventually transformed to the desired tosylate 9 as shown i n S c h e m e I. A number of misadventures attended Scheme I, as might be expected for such hindered substances. Conversion of 1 to diol 2 was sensitive to the residence t i m e with the dilute acid used i n the hydrolysis. Longer contact t i m e s led to removal of 2 t h r o u g h the formation of lactone 10,
0 1979 American Chemical Society
2534 J . Org. Chem., Vol. 44, N o . 14, 1979
Wilt and Niinemae
probably via internal participation5 as shown in eq 3.
Scheme II
b
t
iH2
9 2
-H20
HOCHzCH2 b
10
Lactone 10 could be converted to a sodium salt of the opened acid upon treatment with base, but acidification invariably led back to 10, making it a useless intermediate in the sequence. Formation of the divinyl nitrile 4 by pyrolysis of the diacetate or bis(S-methyl xanthate) of diol 2 was moderately successful, but the purification steps involved made these approaches to 4 less attractive than the route via tosylate 3. Due to its hindered position, the nitrile function in 4 was very resistant to hydrolysis. Only the Ritter reaction6 was found to convert the nitrile to an acid derivative, albeit in only modest yield. Subsequent transformation of the N-tert-butylamide 5 so formed was itself quite difficult.' Apparently the conversion of sp(CN) to sp2(C=O) carbon (4 5 ) , which involves a trigonal intermediate, could be forced, but not the conversion 5 7 wherein a tetrahedral intermediate is involved. Rather a dealkylative fragmentation process using BF, was employed, presumably as in eq 4, to avoid the tetrahedral
-
-0T528 %
r
HX
13, 13a
14,14a
-
FXE
PhCH2
-
OP
7 ?h-C-c\ 9
PhCHz
i
19
6
15
' \NH
intermediate of normal amide hydrolysis and to set up amide 6 for hydrolysis via diazotization with isoamyl nitrite and dry hydrogen chloride. Lastly, reduction of acid 7 with lithium aluminum hydride afforded a lower yield of carbinol 8 than expected. The lower yield was caused by another fragmentation, one related to a reverse aldol condensation,8a as shown in eq 5.
(5) F. Bergel, A. L. Morrison, and H. Rinderknecht, J . Chem. SOC.,267 (1944); R. M. Anker and A. H. Cook, ibid.,806 (1948). (6) L. I. Krimen and D. J. Cota, Org. React., 17, 213 (1969). (7) Cf. N. Sparber, D. Papa, and E. Schwenk, J . Am. Chem. SOC.,70, 3091 (1948).
19
Both ( E ) -and (2)-3-phenyl-1,3-pentadiene (y-phenylpiperylene, 11) were isolated from the reaction and confirmed by comparsion with samples prepared by the literature methodasb The formaldehyde undoubtedly was further reduced to methanol under the reaction conditions but this was not determined. Tosylate 9 was solvolyzed under two sets of conditions: acetic acid buffered with sodium acetate, and dioxanewater (80:20(v/v)) buffered with 2,6-lutidine. The former solvolysis produced a complex mixture containing hydrocarbons (lo%), polymeric material (20% 1, and acetate esters (70%). Only the last substances were investigated. Because the composition of the acetate fraction was thermally sensitive, analysis by NMR spectroscopy was performed in conjunction with authentic mixture^.^ Solvolysis in dioxane-water led to a similar set of products which were grouped by dry-column chromatography. The alcohol fraction again amounted to 70 f 5%. The products formed and the proposed pathway for their formation are given in Table I and Scheme 11, respectively. As indicated there, no electrocyclic closure to a benzylcyclopentenol or its acetate was observed. 2-Benzyl-2-cyclopentenol (19)'O was synthesized independently and was observed to
(8) (a) This uncommon example is testimony for the stability (and therefore good leaving ability) of the highly delocalized 3-phenylpentadienyl anion. (b) K. Alder, J. Haydin, K. Heimbach, K. Neufang, G. Hansen, and W. Gerhard, Justus Liebigs Ann. Chem., 586, 110 (1954). (9) This analysis used synthesized samples for authentic chemical shifts (see Experimental Section) and relied on methylene resonances. The vinyl proton region was too complex for reliable assignment.
/?,P-Divinyl-/?-phenethylTosylate
J . Org. Chem., Vol. 44, No. 14, 1979 2535 Table I. Solvolysis Product Data
___.______-
'H, chem shift datah
X, no.
product ___________ t
/P.> ('
i
xcv2
\\
-+,,
Zb
x
, , /e,
4
6 (alcohol)
Vinyl-Shifted Products 12 2-CH, Cp-CH,
h (acetate)
0.6 b r m 3.98 dd
e
CH, P i I
;
H ?'
4,%,
-3-,
OH, 13 OAc, 13a
20 58
6-CH, 3-CH2
4.28 d 3.28 d
4.67 d 3.30 d
OH, 1 4 OAc, 14a
5 14
6-CH, 3-CH2
4.05 d 3.12 d
4.45 d 3.12 d
OH, 15
35
4-CH,
2.62 d
c
c:.
x
group
12 r
5%
'1L
OH, 1 2 c
compn,O %
OH, 16 OAc, 16a
Phenyl-Shifted Products 12 5-CH, 17 Ph-CH,
4.32 d 3.63 s
4.70 d 3.67 s
8 11
5-CH, Ph-CH,
4.32 d 3.57 s
4.70 d 3.55 s
8
Ph-CH,
2.85 s
31
OH, 1 7 OAc, 1 7 a
x C'.i
OH, 18 c
Fox hydrolysis in aqueous dioxane a t 8 5 ' C; for acetolysis a t 118 'C. Values are precise t o t 2% and were determined by NMR spectral analysis. Because the olefinic products were labile t o conditions, the percentage of each isomer at times varFor all the proied. The values given represent the average reaction mixture. Ranges of i 10% sometimes were observed. ducts other resonances were as follows: Ph H's, 6 7.0-7.5 ( m ) ; vinyl H's, 6 4.9-7.0 (complex m). These regions were too complex for secure diagnostic use. The alcohol products showed HO at 6 2.33-2.45 (broad m, varied with concentration). The acetate products showed a number of CH,COO singlets in the region 6 1.92-2.07 (s). Alcohol 1 2 exhibited the cyclopropyl ring H's a t 6 0.3-0.85 (complex m). ' Product not observed in acetolysis. J = 6-7 Hz in all doublets. e This acetate ( 1 2 a ) was formed in the acetylation of t h e alcohol products ( b CH,COO 4.35, d), presumably because the reaction temperature was lower."
be stable to reaction conditions (dioxane-water, 88 "C, 24 h, p-toluenesulfonic acid and 2,6-lutidine present). Therefore the absence of 19 was not caused by its instability in the reaction or to the workup procedures. Rather in both solvients vinyl-group migration was the principal process observed (72%), with phenyl migration accounting for the baliance of the product." The detection of 12 is especially interesting in that its formation indicates the mode of participation by the vinyl group. No product of retained structure was detected. Clearly k, processes predominate over k, processes in this system in these solvents. Moreover, the vinyl and phenyl group migrations were statistically approximately equal in these k, processes.12a (10) A. I. Chirko, A. F. Matishev,and A. N. Karnitakaya,Zh. Org. Khim., 3,28 (1967), prepared alcohol 19 by air oxidation of 1-benzylcyclopentene. Our sample was prepared by reduction of the corresponding ketone. Its structure was confirmed tiy its mode of formation and spectra (see Experimental Section). (11)The higher temperature used for acetolysis, together with the lability of tertiary and cyclopropylcarbinylacetates in the acidic medium, accounts for the absence of acetates correspondingto 12,15,and 18. Cf. J. H. Babler and D. 0. Olsen, Tetrahea'ronLett., 351 (1974). Admittedly, as pointed out by a referee, the acidic medium was buffered in the present case, unlike that of Rabler and Olsen. However, uncatalyzed (or non-proton-catalyzed) hydrolyses of esters are known. Cf. A. G. Davies and J. Kenyon, Q. Reu., Chem. Soc., 9,203 (1955). Such processes become more facile as the stability of the carbon cation so formed increases, and the entries of 12, 15, and 18 would so qualify. (12) (a)Of special interest is the conclusion that phenyl and vinyl groups have comparable migrating abilities, reached indirectly by comparison of separate cases by R. S. Bly and R. T. Swindell, J. Org. Chem., 30, 10 (19651, and (b) B. Capon, Q. Rec. Chem. SOC.,18, 93 (1964).
Table 11. Acetolysis Rate Constants ana Activation Parameters
compd 9
neophyl tosylate
T,O
"C
100 80 56 (25)'
105h,* s - '
AH*, kcal mol-'
41.4 i 0.7 5.48 I0.04 0.376 i 0.002 (6.02 X lo-*) 25.4 z 0.2 (25)C,d (3.09 x lo-*) 25.8
A S * , eu
-6.54 0.6 -6.3
i
a i 0 . 3 "C. Determined by computer fit. ' Extrapolated from data a t other temperatures. Taken from the data of S. Winstein and A. H. Fainberg, J. A m . Chem. SOC., 78, 2763 (1956), and S. Winstein, B. K. Morse, E. Grunwald, K. C. Schreiber, and J. Corse, ibid., 7 4 , 1113 (1952).
The kinetics of acetolysis were followed titrimetrically and these data may be found in Table 11. From the comparison given in Table 11, tosylate 9 was comparable in rate to neophyl tosylate, a result that must reflect a combination of effects. Although the immense accelerative effect of a homoallylic double bond in 7 norbornenyl substrates is well-known in solvolysis, the situation is less dramatic in other cases. In fact, A participation by homoallylic double bonds in acyclic systems varies with both substrate and conditions.12bThe situation with respect to phenyl ir participation is similar. Within the bounds of the work done in this study (keeping in mind
2536 J . Org. C'hem., Vol. 44, No. 14, 1979
that the objective was the detection of electrocyclic closure and not a measurement of competitive anchimeric abilities), the inductive retardation and anchimeric acceleration observed for the phenyl and vinyl groups in the solvolysis of 9 must be in approximate balance, relative to the case for neophyl tosylate.'2a The competitive ability of both groups to migrate in 9 undoubtedly reflects the comparable stability of the product-forming ion manifolds in each case. Lastly, the failure to observe electrocyclic closure in this investigation may be rationalized. First, vinyl-group migration was more extensive than was originally expected. The ion manifold thus produced cannot so cyclize, thereby reducing the opportunity for success. Second, with regard to the potentially productive phenyl-migrated ion it would appear that insufficient alkylation was present in the vinyl groups, causing the ~ e c o n d a r y 'cyclopentenyl ~ cation 19' to be insufficiently stabilized relative to the pentadienyl cation manifold precursor. This in turn allowed solvent capture to the exclusion of closure and afforded acyclic products only. Future work will therefore search for the closure in highly alkylated bis vinyl analogues of 9.14
Experimental Section Melting points were determined on a calibrated Fisher-Johns block. Boiling points are uncorrected. Gas chromatography was performed on Aerograph Model 920 or A 90-P instruments with helium carrier gas. Infrared spectra were determined on a Perkin-Elmer Model 700A ~pectrophotometer.'~Proton NMR spectra were taken in deuteriochloroform (unless otherwise noted) on a Varian A-60A spectrometer. Microanalyses were performed by Micro-Tech Laboratories. a,a-Bis(,!3-vinyloxyet hy1)phenylacetonitrile (1). This compound was prepared by using a literature procedure16 with only minor modifications: 80%; bp 125-135 "C (0.1 mm); NMR (CC14)6 7.63 s (PhH), 6.46 dd, 4.16 dd, 3.88 dd (CH=CH2, ABX, = 2 Hz), 3.70 t (CHZCHZO, J = 8 Hz), 2.38 Jm = 7, JBX = 14. t (CH2CH20,J = 8 Hz); u (neat) 2260 cm-' (CN). Runs yielding ca. 100 g are easily achieved. a,a-Bis(,!3-hydroxyethyl)phenylacetonitrile (2). Hydrolysis of the vinyl ether 1 was accomplished as r e p ~ r t e d . ' ~ , ' ~The crystalline diol (75%) was used without purification in the next step except for a small sample which was recrystallized from benzene and methanol: mp 95-97 "C; NMR (MezSO-ds) 6 7.50 s (PhH), 3.33 m, 2.21 t (CH2CH20);u (neat) 3300 (OH), 2260 cm-' (CN); lit.16 mp 96-98 "C. a,a-Bis(j3-tosyloxyethy1)phenylacetonitrile(3). Reaction of diol 2 with p-toluenesulfonyl chloride and pyridine in the usual fashion'* afforded tosylate 3: 72%; mp 134-135 "C (chloroform-methanol). Anal. Calcd for CZ6Hz7O6NS2:C, 60.80; H, 5.30. Found: C, 60.55; H, 5.32. a,a-Divinylphenylacetonitrile(4). Potassium tert-butoxide was prepared from the metal (8.85 g, 0.23 g-atom) and dry (13) Increased methylation of pentadienyl cations leads to dramatic increases in cyclization; cf. R. Bladek and T. S. Sorensen, Can. J . Chem., 50,2806 (1972). A significant effect appears to be due to methyl stabilization of the nonplanar "u'* (2,Z) intermediate ion which is the precursor to cyclization. (14) Diazotization of &p-divinyl-fl-phenethylamine[from 4 and LiAIH,: 76%; bp 60-62 "C (0.25 mm); NMR (CDCl,) 6 7.43 s (PhH), 6.26 dd, 5.35 dd, 5.05 dd (CHzCHZ, ABX, Jm = 11, JBX = 18, JAB= 2 Hz), 3.10 s (CH2NHz),0.73 s (CHzNH2);v (neat) 3375 cm-' (NHJ. Anal. Calcd for CI2Hi5N: C, 83.19; H, 8.73. Found: C, 83.19; H, 9.051 at 0 "C in acetic acid followed by 24 h at 25 O C gave an extremely complex mixture that resisted adequate characterization, although cyclization appeared to be absent. Use of such higher energy ions for cyclization thus seems ineffectual also. See ref 2 for details. (15) Only portions of spectra are reported. For complete spectra, see ref 2. (16) F. Bergel, A. L. Morrison, and H. Rinderknecht, J . Chem. SOC., 265 (1944). Cf. F. Bergel, N. Hindley, A. L. Morrison, and H. Rinderknecht, U.S. Patent 2418289, 1947. (17) Hydrolysis t i m e s p a t e r than 10 min (0.2-mol scale) led to mixtures of diol 2 and lactone 10 (viscous oil, no vrN, vro .. 1704 cm-'; lit.6 bp 172 "C (0.1 mm)). (18) R. S. Tipson, J . Org. Chem., 9, 235 (1944). ~
Wilt and Niinemae tert-butyl alcohol (80 mL) by refluxing the materials for 2 h. The solution was cooled to 15 "C and dimethyl sulfoxide (200 mL, recently distilled and dried over calcium hydride) was added. A slurry of tosylate 3 (58 g, 0.113 mol) in further dry dimethyl sulfoxide (200 mL) was added over 30 min, maintaining the temperature at 20 "C or below, with stirring. After 45 min of additional stirring, the white slurry was poured into water (1 L) and extracted with ether (three 150-mL portions). The combined extracts were dried (Na2S04)and evaporated. Distillation afforded the product: 15 g; 85%; bp 80-85 "C (1.0 mm); NMR 6 7.55 s (ArH),6.18 dd, 5.70 dd, 5.46 dd (CH-CH,, ABX, JAB = 2, JAx = 10, JBx= 17 Hz); u (neat) 2250 (CN), 1625,1600,985,925 cm-' (CH=CHZ). Anal. Calcd for Cl2Hl1N: C, 85.17; H, 6.55. Found: C, 85.25; H, 6.63. Olefinic nitrile 4 was also formed (-10% yield) by passage of the diacetate of 2 over glass helices at 450 "C. The products were entrained in a nitrogen stream under a partial vacuum. The product mixture was complex, however, and not easily separable by GLPC. A somewhat better yield (20%) of 4 was obtained by the use of the bis(S-methyl xanthate) ester of 2. Thermal elimination at 250 "C formed 4, but purification from sulfurcontaining byproducts made the route unattractive.2 N-tert-Butyl-a,a-divinylphenylacetamide ( 5 ) . Nitrile 4 (35 g, 0.21 mol) was dissolved in dry tert-butyl alcohol (100 g, 1.34 mol) and glacial acetic acid (350 g). This solution was stirred a t 5 "C as concentrated sulfuric acid (35 g, 0.35 mol) was added dropwise over 4 h. After the addition the mixture was stirred at room temperature for 2 days. The reaction material was poured into ice and water (1.5 L) and extracted with a mixture of ether (10%) in benzene (three 400-mL portions). The combined extracts were washed with sodium carbonate (10% solution) until neutral and then dried (Na2S04). After evaporation of the solvent, distillation yielded forecuts of polyisobutylene and recovered nitrile 4 (ca. 40-50% recovery), followed by the desired amide 5 (21 g; 40%, bp 85-100 "C (0.1 mm)), which solidified on standing. A portion was recrystallized twice from hexane: mp 51-52 "C; NMR 6 7.35 s (PhH), 6.48 dd, 5.38 dd, 5.00 dd (CH=CH2, ABX, J M = 11, J B X = 17.5, JAB = 1.5 Hz), 5.53 broad (NH),1.31 s (t-Bu); u (melt) 3440 (NH), 1680 cm-' (C=O). Anal. Calcd for CI6HzlON: C, 78.97; H, 8.70. Found: C, 78.96; H, 8.74. a,a-Divinylphenylacetamide(6). Amide 5 (30 g, 0.12 mol), tetrachloroethylene (500 mL), and boron trifluoride etherate (60 mL) were stirred while under reflux for 20-24 h. Ice (200 g) was added to the cooled material which was then stirred for 2 h. The organic layer was separated, washed with water (200 mL) and sodium bicarbonate (5% solution) until neutral, and then dried (Na2S04). The solvent was evaporated and the solid residue was crystallized from ether-hexane: 21 g; 91%; mp 60-61 "C (after two further recrystallizations); NMR 6 7.50 s IPhH), 6.60 dd, 5.41 dd, 5.11 dd (CH=CH2, ABX, J a = 11,JBx = 18,JAB= 1.5 Hz), 5.96 broad (NH,); u (melt) 3500-2900, 1600 tCONH,), 1600,939 cm-' (CH=C H,) . Anal. Calcd for Cl2HI3ON: C, 76.98; H, 7.00. Found: C, 77.30; H, 7.00. Amide 5 was completely resistant to normal acid or base hydrolysis. a,a-Divinylphenylacetic Acid (7). A solution of amide 6 (21 g, 0.11 mol) in dioxane (300 mL) was chilled in an ice bath and saturated with hydrogen chloride gas. Dropwise addition of isoamyl nitrite (50 mL, 0.36 mol) to the cold (10 "C), stirred solution was then performed over 2 h. The solution was allowed to come to room temperature and stirred for an additional 2 h, after which time it was heated under reflux for 3 h. The dioxane was evaporated and the residue was taken up into ether (200 mL). The ether solution was extracted with sodium carbonate solution (lo%, three 75-mL portions), and the alkaline extracts were then acidified with hydrochloric acid (10%). The precipitated material was extracted into ether (two 100-mLportions) and the combined extracts were dried (Na,SO,) and evaporated. The residue was chromatographed over Florisil (1 in. X 6 in. column), using 30% ether in hexane (600 mL) as the eluant. Evaporation produced crystalline acid (18 g, 87%), a portion of which was purified by crystallization thrice from hexane: mp 67.5-68 "C; NMR 6 12.4 s (COOH), 7.53 s (PhH), 6.63 dd, 5.56 dd, 5.10 dd (CH=CHZ,
,8,@-Divinyl-@-phenethyl Tosylate ABX, J a = 11,JBX = 113, JAB = 0.5 Hz); v (melt) 330~2400,1701 cm-' (C'OOH). Anal. Calcd for Cl2Hl2O2:C, 76.57; H, 6.43. Found C, 76.70; H, 6.51. Attempts to hydrolyze nitrile 4 to either acid 7 or amide 6 by the following reactions gave only recovered starting material: refluxing concentrated hydrochloric acid; sodium ethoxide in refluxing ethanol; and potassium hydroxide in refluxing ethylene glycol. &j3-Divinyl-@-phencathyl Alcohol (8). Reduction of acid 7 (17 g, 0.09 mol) with lithium aluminum hydride (5.0 g, 0.135 mol) in dry ether in the usual fashion (25 "C, 1 h) led to a forecut mixture of ( E ) -and (2,-y-phenylpiperylene (bp 40-45 "C (1.5 mm)), aeparable by GL,PC (140 "C, OV-1 column) into the 2 isomer (NMR 6 1.6 d. J = 7 Hz (CH,)) and the E isomer (NMR 6 1.93 d, J = 7 Hz (CHt1)),15 confirmed by comparison with authentic material (lit.8hbp 72-73 "C (12 mm)), and alcohol 8: 9.4 g; 60%; bp 94-95 'C (1.5 mm); NMR 6 7.48 s (PhH), 6.78 dd, 5.40 dd, 5.16 dd (CH:=CH, 4BX, JAX = 11,JBX = 18, JAB = 2 Hz), 3.95 s (CH20H),2.18 s (CHzOH); v (neat) 3400 (OH). A spinning-band 40-plate distillation column was used to separate these products efficiently. Anal. Calcd for CI2Hl40:C, 82.72; H, 8.10. Found: C, 82.62; H , 8.33. The acetate of 8 was made from the alcohol and acetic anhydride (reflux for 1 2 h). Both alcohol 8 and its acetate were adjudged absent from the solvolyses on the basis of their CHzO resonances, 6 4.41 for the latter. p$-Divinyl-@-phenethylTosylate (9). Reaction of alcohol 8 (5.2 g, 0.03 mol) with recrystallized p-toluenesulfonyl chloride (8.0 g, 0.042 mol) in dry pyridine (20 mL) a t 25 "C for 48 h led, after the normal processing, to tosylate 9 (7 g, 70%), which was crystallized thrice from hexane to afford the solvolysis reactant: mp 53-54 "C; NMR 6 7.49 q (ArH, AzBz,J = 8 Hz), 7.25 s (PhH), 6.05 dd, 5.28 dd, 4.98 dtl (CH=CHz, ABX, J A X = 11, J s x = 17, JAB= 2 Hz), 4.33 s (CH,OTs), 2.41 s (ArCH,); u (melt) 1355, 1170 cm-' (-SOz-). Anal Calcd for Cl9HZ0O3S:C, 69.48; H, 6.14. Found: C, 69.31; H, 6.15. a,a-I)ivinyl-j3-phenethyl Alcohol (18). Vinyllithium (Alfa Inorganics, 45 mL of a 2.2 M solution in tetrahydrofuran) was stirred while being treated dropwise under nitrogen with a solution of ethyl phenylacetate (8.21g, 0.05 mol) in freshly distilled, dry tetrahydrofuran. The 4 5-min addition was followed by 30 min of further stirring. An ziqueous solution of ammonium chloride (IO%, 30 mL) was added slowly, followed by water (250 mL). The layers were separated and the aqueous layer was extracted with ether (two 10-mL portions). The organic phase and the ether extracts were combined, dried (NazS04),and evaporated. The oily resxdue was chromatographed on alumina (activity 1, 150 g), eluting first with hexane (300 mL) to remove mineral oil (from the vinyllithium sample) and then with ethyl acetate (200 mL) to obtain the alcohol. R.emova1 of the ethyl acetate followed by distillation through a 40-plate column yielded alcohol 18: 4.1 g; 47%; bp 50-51 "C (0.07 mm); NMR 6 7.36 s (PhH), 6.13 dd, 5.25 dd, 5.13 dd (CH==CHz,ABX, JAX = 11, J B X = 18, J A B = 2 Hz), 2.90 s tCHzPh), 1.70 s (OH); v (neat) 3560, 3460 cm-' (OH). Anal. Calcd for ClSlHl4O:C, 82.72; H, 8.10. Found: C, 82.60; H, 8.17. Use of vinylmagnesium bromide in the above process led to a poorer yield of 18 which was contaminated with a ketone, presumably l-phenyl-5-lrlexen-2-one (NMR 6 3.67 s (PhCHzCO), 2.43 t (COCHzCHz))formed by conjugate addition to benzyl vinyl ketone (the intermediate first formed from the ester). 2-Benzyl-2-cyclopenten-1-01 (19). 2-Benzalcyclopentanone was prepared as reported.lS Its isomerization to 2-benzyl-2cyclopentenone was achieved as describedz0in 43% yield. Reduction to alcohol 19 WELSaccomplished with lithium aluminum hydride, following the procedure reported for reduction of the benzal isomer:'' 7470,distilled in a Kugelrohr apparatus a t 105 "C (0.35 mm); NMR CC 7 23 s (ArH), 5.43 broad s (=CH), 4.58 m (19) A. P. Phillips and J. Mentha, J . A m . Chem. SOC.,78, 140 (1956). (20) M. Elliott, N . F. Janes, and M. C. Payne, J . Chem. SOC.C, 2548 (1971). (21) H. 0. House and R. L. Wasson, J. Am. Chem. SOC.,78,4394 (1956).
J . Org. Chem., Vol. 44, N o . 14, 1979 2537 (CHOH), 3.43 s (ArCH,), 2.65-1.57 m (OH, 4,5-CHz's); v (neat) 3350 broad (OH), 1607 (C=C), 1050 cm-' (CO); lit.'O b p 91-92 "C (0.2mm). This alcohol was recovered in essentially quantitative yield upon treatment under the exact hydrolysis conditions and workup used for 9 (see below). No spectral evidence for isomerization was found. The benzyl resonance at 6 3.43 was not observed in the NMR spectrum of the hydrolysis product from 9, indicating the absence of 19 in this solvolysis. Acetolysis of Tosylate (9). Tosylate 9 (1.0 g, 3.04 mmol) and sodium carbonate (0.193 g, 3.65 mmol of potential sodium acetate) were dissolved in purified acetic acid containing 1% (v/v) acetic anhydride (121 mL). The mixture was heated a t reflux under nitrogen for 24 h. The cooled solution was poured into ice water (1 L) and extracted with methylene chloride (three 100-mL portions). The combined extracts were washed with aqueous saturated sodium bicarbonate until the washes were basic, and then they were dried (NazS04)and evaporated. The residual oil was distilled at 0.15 mm in a Hickman microstill (bath temperature 60-80 "C) to separate the volatile products from nonvolatile polymeric material. The distillate was chromatographed on a dry column of Florisil, using 99:l hexane-ether as the eluant. This procedure removed hydrocarbon product. Elution with 50:50 hexane-ether was then performed. The oil so obtained was again distilled as above to afford the solvolysis acetates as a colorless oil: 250 mg; 39% yield. Anal. Calcd for C14H1602 (mixture): C, 77.75; H, 7.45. Found: C, 77.67; H, 7.64. Investigation of the crude product subsequently, using spectral properties established from authentic samples, indicated 70% ester, 10% hydrocarbon, and 20% polymer product in the acetolysis. Attempted separation of the acetate esters by GLPC at 200 "C (Reoplex column, 1/4 in. X 6 ft) led to extensive isomerization and decomposition. Catalytic hydrogenation (Pd/C, 25 "C, 15 min) converted the acetates into saturated material. The NMR spectrum of the saturated product was consonant with that expected for a mixture 3-phenyl-1-hexyl acetate and 3benzyl-1-pentyl acetate. The only fruitful approach adopted was to analyze the distilled acetate fraction by NMR, using Schoolery's valuesB expected for the various possibilities together with probable coupling constants. By this method the data in Table I were garnered. The phenyl-shifted acetates 16a and 17a were easily observed by comparison with those formed from alcohol 18 upon standing in acetic acid containing a trace of sulfuric acid. Hydrolysis of Tosylate 9. Into purifiedz4dioxane (240 mL) and distilled water (60 mL) were added tosylate 9 (2.5 g, 7.61 mmol) and 2,6-lutidine (0.823 g, 7.68 mmol). The mixture was flushed with nitrogen and maintained at 85 "C under nitrogen for 24 h. The solvent was removed to a volume of 150 mL, keeping the temperature below 50 "C. Water (200 mL) was added and the mixture was extracted with ether (three 100-mL portions). The combined extracts were washed with dilute hydrochloric acid (5%, 100 mL), water (100 mL), and saturated aqueous sodium bicarbonate (150 mL). The material was dried (NaZSO4)and evaporated. The crude product was chromatographed on Florisil (200 g) deactivated with water (10 g) and ethyl acetate (5 g), using the dry-column technique.z5 Elution with hexane-ethyl acetate (95:5, 260 mL) afforded the viscous alcohol products (900 mg, 68%). The analysis of the product was again by NMR spectroscopy as with the acetates. Confirmatory evidence for the products was obtained by acetylation (100 mg of alcohol mixture, 150 mg of acetic anhydride, 2 mL of benzene, 24 h) to mixtures of acetates which were then compared to those from acetolysis of 9. Aside from the absence of acetates of alcohols 12, 15, and 18 (cyclopropylcarbinyl and tertiary alcohols), the acetate and alcohol mixtures conformed in structure although compositions varied."
-
(22) D. J. Cram and F. L. Harris, Jr., J. Am. Chem. SOC.,89,4642 (1967). (23) For a convenient list, see A. J. Gordon and R. A. Ford, "The Chemist's Companion", Wiley, New York, 1972, p 257. (24) L. F. Fieser, "Experiments in Organic Chemistry", 3rd ed., D. C. Heath, Boston, Mass., 1957, p 285. (25) J. M. Boha, M. M. Jouillie, F.A. Kaplan, and B. Loev, J. Chem. Educ., 50,367 (1973); B. Lcev and M. M. Goodman, Chem. Ind. (London), 2026 (1967).
2538 J . Org. Chem., Vol. 44, No. 14, 1979
Helgeson, Tarnowski, a n d Cram
The presence of 18 was confirmed through authentic comparison; those of 12 and 15 are based upon spectral assignment. Kinetic Study on Tosylate 9. Purifiedzzacetic acid containing acetic anhydride (1% (v/v)) was the solvent. The reactions were performed on a 0.03-M scale in the presence of sodium acetate (0.04 M). The well-known titrimetric procedure was followed, using crystal violet (0.03% solution in acetic acid) as indicator and standardized p-toluenesulfonic acid as the titrant. The kinetic data were processed by computer for the values in Table 11.
Acknowledgement is m a d e t o the donors of t h e Petroleum Research F u n d , administered b y the American
Chemical Societv. “ , for s u m o r t of t h i s research. &
I
Registry No. 1, 70179-05-4; 2, 10469-27-9; 3, 70179-04-3; 4, 70179-03-2;5, 70179-02-1;6, 70179-01-0; 7, 70179-00-9;8, 70178-99-3; 8 acetate, 70178-98-2;9, 70178-97-1; 12, 70178-96-0; 13 (X = OH), 70178-95-9;13 (X = OAC),70178-94-8;14 (X = OH), 70178-93-7;14 (X = OAC),70178-85-7;15, 53847-13-5;16 (X = OH), 70178-86-8; 16 (X = OAC),70178-87-9; 17 (X = OH), 70178-88-0; 17 (X = OAC), 70178-89-1;18, 38553-10-5; 19,13694-30-9;tert-butyl alcohol, 75-65-0; (E)-y-phenylpiperylene, 70178-90-4; (2)-y-phenylpiperylene, 64035-02-5; 2-benzalcyclopentanone, 5679-13-0; 2-benzyl-2-cyclopentenone, 22354-39-8; 3-phenyl-1-hexyl acetate, 70178-91-5; 3benzyl-1-pentyl acetate, 70178-92-6.
Host-Guest Complexation. 19. Cyclic, Bicyclic, and Tricyclic Polyether Systems122 Roger C. Helgeson, Thomas
L. Tarnowski, and Donald J. Cram*
Department of Chemistry, University of California at Los Angeles, Los Angeles, California 90024 Received J a n u a r y 18, 1979
Eighteen new macrocyclic polyethers are described, many of which are multistranded. The free energies of complexation in CDC13 at 25 “C of these hosts with Lit, Nat, Kt, Rb+, Cst, and NH4’ picrates are reported. In the following line structures, the letters stand for the following units: E is CH,CHz; M is CH,; D is 1,l’-dinaphthyl substituted in the 2,2’-positions by OCH3, OH, or (OE),O bridges and in the 3,3’-positions by M(OE),OM or (OE),O bridges or CH3 groups; T is 1,l’-ditetralyl substituted in the 2,2’-positions by (OE),O bridges and in the 3,3’-positions by H, M(OE),OM, or M(SE),SM bridges. The substituents (or bridges) attached to the 2,2’-positions of the units designated as D or T are written on the right, whereas those attached to the 3,3’-positions are written on the left, the exception being when two D or T units are involved. When bridges connect the 2- and 3-positions to one another, the bridges are written on both sides. The hosts containing a single bridge connecting the 3,3’-positions of D are as follows: E(OEOM),D(OCH3),, 8; O(EOEOM)2D(OCH3)2,9; E(OEOEOM)2D(OCH3)2, 10; E(OEOM),D(OH),, 11; O(EOEOM),D(OH),, 12; E(OEOEOM),D(OH)z, 13. Hosts containing two bridges connecting the 2- to the 2‘- and 3- to the 3’-positions are O(EOEOM),D(OEOEO),E, 16, and E(OEOEOM),D(OEOEO),E, 17. An example of a host with two bridges connecting two D units through their 2,2’-positions and a bridge connecting the 3,3’-positions of one D unit is O(EOEOM),D(OEOEO)zD, (S,S)-19. For comparison, host (CH3)2D(OEOE0)zE(35), whose bridge connects the 2,2’-positions, was included. The -AGO,, values (kcal/mol) for each host binding the six ions decreased in the following order: O(EOEOM),D(OEOE0)2E (8.7), Nap(OEOEO),E (8.7), (CH,),D(OEOE0)2E (8.5),E(OEOEO)zD(OEOE0)2E(8.2), O(EOEO),MDM(OEOE),O (8.2), BrNap(OEOEO)zE (7.9), E(OEOM),D(OCH3), (7.8), O(EOEOM)2D(OCH3)2(7.4), (R,S)-T(MOEOM),(OEOE0)ZT (7.1), E(OEOEOM)2D(OCHJ, (6.8), (R,R)(S,S)-T(MOEOM),(OEOEO),T (6.7), O(EOEOM),D(OH), (6.61, E(OEOEOM)zD(OH)z(6.4), Br,Nap(OEOEO),E (5.8), E(OEOM),D(OH), (5.5), (R,R)(S,S)-(CH,O),D(24.6). A similar order was followed for maximum (MOM)zD(OCH3)z(4.9), (R,R)-T(MSESM)z(OEOEO)zT selectivity in binding the six ions, as measured by -A(AGo)mm (kcal/mol). The values ranged from a high of 5.3 kcal/mol for O(EOEOM)2D(OEOE0)2E to a low of 0.5 kcal/mol for (R,R)(S,S)-(CH30),D(MOM),D(OCH3)2. The four-stranded host with the most enclosed cavity, (R,R)(S,S)-T(MOEOM),(OEOEO),T, gave the relatively high -A(AG”)- of 4.3 kcal/mol for its relatively low -AGO,, of 6.7 kcal/mol. This host gave the very high -AGO difference of 3.7 kcal/mol for Kt and Cs’. The highly rigid host with seven well-organized oxygen binding sites, O(EOEOM)zD(OEOEO),E, gave the highest -AGO value of 11.1kcal/mol for Kt. The two hosts with “jaws”-type organization of 10 to 12 oxygen binding sites, E(OEOEO),D(OEOEO),E and O(EOEO),MDM(OEOE),O, gave the highest -AGO values (kcal/mol) observed for Cst of 9.3 and 9.2, respectively. Their complexes with the larger ions probably possess a sandwich-type structure. Hosts containing two D units with bridges connecting the 3to 3- and 3’- to 3’-positions are (CH30)2D(MOM)zD(OCH3)z, (S,S)-20 and (R,R)(S,S)-20, and (HO),D(MSM)zD(OH),, (R,R)(S,S)-22. Stereoisomeric hosts containing two T units with bridges connecting their 2- to 2- and 2’- to 2’-positions are T(OEOEO)zT,(R,S)-23 and (R,R)(S,S)-23. Stereoisomeric hosts containing two T units with two (OE)zO bridges connecting their 2- to 2- and 2’- to 2’-positions and two other kinds of bridges connecting their 3- to 3- and 3’- to 3’-positions are T(MOEOM),(OEOEO),T, (R,R)-25, (R,R)(S,S)-25,and (R,S)-25, and T(MSESM)Z(OEOEO),T, (R,R)-26. Two hosts with bridges connecting the 2- to the 3- and 2‘- to 3’-positions of a D unit are E(OEOEO)zD(OEOEO),E,27, and O(EOEO),MDM(OEOE)zO(M’s a t 3,3’-positions), 34. Hosts based on 2,3-naphtho-18-crown-6 (30), Nap(OEOEO),E, with Br in their 1- or 1- and 4-positions are BrNap(OEOEO),E, 31, and BrzNap(OEOEO),E, 32.
The literature is rich in descriptions of macrocyclic ligand systems synthesized t o complex alkaline metal ions.3 (1) The authors thank the Division of Basic Sciences of the Department of Energy for a contract (AT(04-3)34, P.A. 218), which supported this research. (2) Two small parts of this paper appeared as parts of previous Communications: (a) K. E. Koenig, R. C. Helgeson, and D. J. Cram, J . Am. Chem. SOC.,98,4018-20 (1976); (b) T. L. Tarnowski and D. J. Cram, J . (?hem. SOC.,Chem. Commun., 661-3 (1976).
0022-326317911944-2538$01.00/0
The cavities of m o s t of these hosts are defined b y a monocycle whose chain is conformationally flexible enough
so that the binding sites can be nearly coplanar or t h e i r chains can coil i n a variety of ways to adapt to the propensities of potential metal ion guests. A relatively small (3) J. S. Bradshaw in “Synthetic Multidentate Macrocyclic Compounds”, R. M. Izatt and J. J. Christensen, Eds., Academic Press, New York, 1978,
Chapter 2
1979 American Chemical Society
